Dosing

Adults (18 years and older):

Various doses of nettle have been used in clinical trials; however, none have been proven effective. For benign prostatic hyperplasia (enlarged prostate), 1-2 capsules of Bazoton® containing 300 milligrams extract of Radix urticae; ERU) has been taken twice daily for up to six months. Bazoton® Liquidum has also been studied in doses of 3 milliliters twice daily for three months. For allergic rhinitis, 600 milligrams freeze dried nettle at the onset of symptoms for one week has been used. As an extract, nettle has traditionally been given in doses of 30-150 drops daily for six months.

Children (younger than 18 years):

There is no proven safe or effective dose for nettle in children.

Safety

DISCLAIMER:
Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

Allergies

Avoid in individuals with a known allergy or hypersensitivity to nettle, the Urticaceae family or any constituent of nettle products. Two patients taking a freeze-dried preparation of Urtica dioica for the treatment of allergic rhinitis had intensification of allergy symptoms.

Side Effects and Warnings

Nettle therapy was generally well-tolerated for up to two years in available human trials. However, contact with the hairs of the nettle plant may cause short-lived whealing ("hives"), burning, itching, localized rash and a prolonged tingling sensation. Other reported side effects include continual pain in the gastrointestinal tract, hyperperistalsis (excessive rapidity of the passage of food through the stomach and intestine), and mild gastric discomfort when the medication was taken on an empty stomach. Patients taking Bazoton® capsules have experienced side effects such as constipation, diarrhea and gastric disorder.

The nettle plant contains a substance that is a coumarin derivative. Nettle may increase the risk of bleeding. Caution is advised in patients with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Although not well studied in humans, nettle may increase blood glucose, but not likely enough to be of clinical concern. Nonetheless, use cautiously in patients with diabetes mellitus due to potential increased glycemia. Monitor blood glucose levels.

Although not well studied in humans, nettle may cause diuresis (water loss, excessive urination), uterine contractions, or low blood pressure. Use with caution in patients with hyponatremia (low sodium levels in the blood) as nettle has a synergistic diuretic effect. Monitor sodium levels.

Elderly persons should use nettle cautiously for a possible hypotensive (decreased blood pressure) crisis that might be affected by nettle. Nettle should not be administered to children as it has not been studied.

Pregnancy and Breastfeeding

Nettle is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence. In theory, nettle may induce uterine stimulation.